diff --git a/doc/osmocom-authn-protocol.txt b/doc/osmocom-authn-protocol.txt
index 1b6794e..6d057be 100644
--- a/doc/osmocom-authn-protocol.txt
+++ b/doc/osmocom-authn-protocol.txt
@@ -142,14 +142,14 @@
   02	Cause			GMM cause,		M	TLV	3
 				04.08: 10.5.5.14
 
-3.2.6. Register Result
+3.2.3. Register Result
 
 Server -> Client
 
   IEI	Info Element		Type			Pres.	Format	Length
 	Message type		4.2.1			M	V	1
 
-3.2.3. Challenge
+3.2.4. Challenge
 
 Server -> Client
 
@@ -158,7 +158,7 @@
   20	RAND			octet string (16)	M	TLV	18
   23	AUTN			octet string (16)	M	TLV	18
 
-3.2.4. Challenge Error
+3.2.5. Challenge Error
 
 Client -> Server
 
@@ -167,7 +167,7 @@
   02	Cause			GMM cause,		M	TLV	3
 				04.08: 10.5.5.14
 
-3.2.5. Challenge Result
+3.2.6. Challenge Result
 
 Client -> Server
 
@@ -175,7 +175,7 @@
 	Message type		4.2.1			M	V	1
   21	XRES			octet string (8)	M	TLV	10
 
-3.2.3. Sync Request
+3.2.7. Sync Request
 
 Client -> Server
 
@@ -183,14 +183,14 @@
 	Message type		4.2.1			M	V	1
   20	AUTS			octet string (16)	M	TLV	18
 
-3.2.4. Sync Error
+3.2.8. Sync Error
 
-Server -> Client
+Not used.
 
-  IEI	Info Element		Type			Pres.	Format	Length
-	Message type		4.2.1			M	V	1
-  02	Cause			GMM cause,		M	TLV	3
-				04.08: 10.5.5.14
+3.2.9. Sync Result
+
+Not used.
+
 
 4. Information Elements